Redescription of Myxobolus pyramidis Chen, 1958(Myxosporea: Bivalvulida).

Redescription of Myxobolus pyramidis Chen, 1958, from gill lamellae of allogynogenetic gibel carp, Carassius auratus gibelio (Bloch), is presented in this paper to complete Chen's description. The diagnostic characters of the myxosporidia are: ovoid round, greyish-white polysporous plasmodia, averaging (159+/-21)x(72+/-6.5) mum in size; spore pyriform in front view with smooth surface and symmetrical valves, convex-shaped in sutural view with straight and thick sutural line, averaging (10.5+/-1.1)x(10.3+/-0.9)x(6.1+/-0.2) mum in size; two equal pyriform polar capsules averaging (5.5+/-0.7)x(3.5+/-0.2) mum in size with distinct intercapsular process and polar filament wounded in five to six coils. The histological effects of the pathogen were observed by light microscopy, and the parasite-host relationship was discussed.